Side by side
Pick two or three seeds to see how they grow, side by side: sprouting, spacing, sun, water, frost and pet safety in one table.
Comparing Giant Sunflower vs. Mexican Sunflower vs. Ageratum
The comparison
| Fact | | | |
|---|---|---|---|
| Difficulty | Easy | Easy | Easy |
| Life cycle | Annual | Annual | Annual |
| Germination time | 7–14 days | 7–14 days | 7–21 days |
| Germination temperature | 21–24 °C70–75 °F | 21–29 °C70–84 °F | 24–27 °C75–81 °F |
| Sowing depth | Not yet verified | Not yet verified | On the surface |
| Spacing between plants | 61–76 cm2–2½ ft | 61 cm2 ft | Not yet verified |
| Sun | Full sun | Full sun | Full sun, partial shade |
| Water | Not yet verified | Low | Moderate |
| Containers | Not yet verified | Not yet verified | Yes |
| Frost tolerance | Not yet verified | Not yet verified | Tender (no frost) |
| Soil pH | pH 6.0–7.5 | Not yet verified | Not yet verified |
| Links |
Up close
What each one is, in a few lines, with the full growing guide one click away.
FlowersHelianthus annuus
Giant sunflowers (Helianthus annuus) are very tall annuals grown from seed after the last frost in full sun. Species plants can reach about 10 feet (305 cm), and some giant cultivars grow taller.
How to grow giant sunflowerFlowersTithonia rotundifolia
Mexican sunflower (Tithonia rotundifolia) is a fast-growing warm-season annual with orange flowers that draw bees and butterflies. It thrives in full sun and poor soil, making it an easy choice for beginners.
How to grow mexican sunflowerFlowersAgeratum houstonianum
Ageratum is a frost-tender annual with fluffy blue, pink or white flower clusters that is usually started from seed indoors about 8 to 10 weeks before the last spring frost.
How to grow ageratumKeep comparing
Add a third seed, or swap one for a close relative from the same category.
Giant Sunflower vs. African DaisyGiant Sunflower against another flowerMexican Sunflower vs. African DaisyMexican Sunflower against another flowerAgeratum vs. African DaisyAgeratum against another flower
Giant Sunflower vs. African MarigoldGiant Sunflower against another flowerMexican Sunflower vs. African MarigoldMexican Sunflower against another flowerAgeratum vs. African MarigoldAgeratum against another flowerThe table, row by row
Every row is a fact from each seed's own profile, lined up so the differences stand out.
Germination time and temperature
How many days the seeds take to sprout, and the temperature range they sprout in.
Sowing depth and spacing
How deep to sow each seed and how far apart the plants should grow. “On the surface” means the seed isn't covered.
Days to maturity and life cycle
How long until the plant is ready, counted from sowing or from transplanting (each value says which). Annuals live one year, biennials two, perennials longer.
Sun and water
Full sun means 6 or more hours of direct sun a day, partial shade a few hours. Water needs are rated low, moderate or high.
Containers, frost tolerance and soil pH
Whether it grows in a pot, with the smallest pot when it's known. Frost tolerance runs from tender (no frost) to hardy. Soil pH 7 is neutral.
Toxicity to cats and dogs
Whether the plant is toxic to cats and dogs.
Quick wins
Days from sowing until the first shoots appear, in good conditions.
Pet friendly
Listed as non-toxic to both cats and dogs. Each seed's page has the details.
Not safe for pets: borage, buckwheat, caraway, carnation and 14 more.
Comparing
Each seed's page explains how to grow it from seed, with facts researched and reviewed by our editors.
